Seal for gas pickling furnace muffles



Jan. 9, 1945. R. F. RENKIN I SEAL FOR GAS PICKLING FURNACE MUFFLEb 2 Sheets-Sheet 2 Filed Aug. '10, 1942 Patented Jan. 9, 1 945 sEAL FOR: GAS PICKLING FURNACE MUFFLES Robert F. Renkin, Sharon,'Pa., assignor of onehaif to Henry A. Roemer, Pittsburgh, Pa.

Application August10, 1942, Serial No. 454,234

' A still' furtherobject is to provide a simple 6 Claims.

The invention relates'to an improved construction'for providing a seal for a gas chamber, and more particularly to improved sealing means for the discharge end .of a gas pickling furnace muffiein'which continuous strip metal and the like is treated. p I 1 I In coating steel products, as for example steel strips, wire and the like, with zinc, tin and other metals of low melting points, it is necessaryto clean the surfaces of the steel product to prepare it for coating. The cleaning may be desirably eifected by means of a dry pickle treatment instead of the ordinary wet pickle treatment in l which an acid bath is utilized, and a method of coating steel strips or wire including such fdry pickle. treatment is set forth in my prior Pat ent No. 2,245,225, issued June 10, '1941 and entitled Method of coating metal. I

In cleaning steel strip, for example, by means of this dry pickle treatment. prior tocoating', the strip is passed through a long closed mufile tube located within a heating furnace, and'a heated controlled active atmosphere or pickling gas is passed through the muffie tube preferably in a direction counter to the travel of the strip. The pickling gas is'adapted forreactin'g with the scale and other surface impurities'on the strip to form gases or vapors which are carried off with the pickling gas passing through the muflle.

At its discharge end, the mufile tube extends downwardly into a hot water' or fiuxing bath, and it is very important to provide'sealing means around the strip where it discharges from the mufile into the bath in order to prevent the es-' cape of pickling gas and to prevent the vapors from the bath from'entering into the mufile tube.

Moreover, continuous strip consists of coils having their ends welded together forming thickened and uneven joints, and accordingly the sealing means must be adapted to allowthe joints to ,pass therethrough, and at the same time to provide a seal around the strip intermediate such joints.

but extremely effective sea] at the discharge end of a gas pickling fu'rnacejmuflia 'which seal pre-' vents gases from entering or leaving the mufile as the strip discharges'therefrom.

These and other objects are accomplished by the improvements comprising the present invention, which may be stated in general terms as including vertically spaced'pairs of sealing rollers mounted in'the depending vertical discharge I portion bf a'mufile tube, said rollers being yieldingly held in engagement with'opposite surfaces of a strip passing through the muflle tube, and being rollably supported on inclined supports sloping downwardly in opposite directions toward the strip.

"While, the invention is shown and described herein as appliedto cleaning strip steel prior to coating, it will be understood that the invention includes thetreatment of other products such as sheets, strip sheets, rodsor wire, without departing from the scope of the appended claims.

Referringlto the drawings forming part hereof,

Figure 1 is' a fragmentary vertical sectional view through discharge portion of a gas pickling furnace muflie, with certain parts in elevation; Fig. 2 is .a transverse sectional view thereof ason line 2-4, Fig. l; and I Fig. 3 is a fragmentary sectional view as on line 3-3,Fig. 2. I I

Similar numerals 1 refer to similar parts throughout the several views of the drawings.

In Fig. 1 of the drawings the vertically extending discharge portion of a gas pickling furnace mufile is shown fragmentarily. The'lower section 3 of saidmufiie portionextends intoa water seal W provided bythe channel 4 around the hot water or fluxing tank T into which the steel strip, 5 passes preparatory to being coated. The tank T is detachably connected to the section 3 of the mufile portion by'bolts 4a hung from ears 4b on section 3..-

It is therefore a general object of the present invention to provide a noveland improved sealing construction for a gas chamber in which a continuous strip or the like is being treated.

Another and more specific object isto provide improved sealing means for the discharge end of a gas pickling furnace muifie. l 1

.A further object is to provide an improved sealing construction at the discharge end of a gas pickling furnace mufliefor sealing around a continuous strip having joints and passing vertically through the mufile.

I p The upper section 5 of the muflle discharge portion is connected to the dischargeend of a horizontal. muflle'tube extending through a gas pickling'furnace, such as shown in my 'copending application Serial No. 444,502, filed May 26, 1942 and entitled Furnace muflie construction.

vThe steel strip S iscleaned or pickled in the horizontal muffle tube by the action of the pickling gas circulating therethrough, and as the strip passes downwardly through the vertical discharge portion of the mufile and then into the washing or fiuxing tank T, the improved sealing means constituting the present invention prevents the escape of the pickling. gas and prevents the vapors from the washing or fluxing tank from enterin the mufile tube.

As shown, the vertical discharge portion of the muffle tube is made up of a number of tubular sections including lower end section 3, top section 5, and intermediate sections 6 and 1. Additional sections may -be used as required for making the connection with the horizontal portion of the muflie tube.

The top section 5 of the muille tube discharge I upper sealing rollers l5 has an .outturned flange i.

:1] which is clamped between .the flanges I l and I3 for mounting the support 14 in the mufile tube discharge portion.

A similar support 1.8 .for supporting the lower seal-ing rollers I9 is secured to or .made integral with the lower end section 3, as shown, and the lower end of intermediate section 5 is provided with an outturned flange which is bolted to the flange portion 2| of the bottom section 3 by means of bolts .22. The sealing roller supports M and 1-8 have upper surfaces 23, one .on each side of the strip S, and said surfaces 23 are inclined downwardly in opposite directions toward the strip S. The rollers l5 and 43 are rollably supported at their peripheral or strip engaging surfaces .on the inclined surfaces 23 and tend by gravity to reliably engage opposite surfaces of the strip A.

Between the oppositely inclined surfaces 23, the supports M and ,1 8 are provided with slots 24 and 25 respectively, through which the strip passes.

The sealing roller supports l4 and I8 are provided at their ends with upwardly extending flange portions 26 and 21 respectively, and as shown in Figs. .2 and 3, said flange portions are adapted to slidably abut the ends .of the sealing rollers I5 and .13 respectively, so as to substantially prevent any leakage of gas or vapor around the ends of the rollers and through the :slots 24 and 25 in the supports I 4 and I8.

The means for yieldingly urging :each of the sealing rollers 15 and 19 toward the strip preferably comprises spring pressed .plungers 28 hav- 30 of the plunger and acting between the plunger 28 and a washer 3| on said reduced portion. The washer 3| abuts an internal annular flange v32 in a cap 33, which is preferably screwed on a projecting tubular portion 34. The tubular projections .34 are preferably integral with the mufile sections 6 and 1, and the plungers 28 are slidable therein. Preferably the caps 33 are provided with perforated ears 35 for facilitating attachment and detachment of the caps 33 from the projections 34.

A plurality of plungers 28 may be provided for each of the rollers I5 and I9, and as shown in Fig. 2, two plungers are provided for each roller, although more may be provided, if e red.

The vertically spaced pairs of sealing rollers I5 and I! are partially self-aligning because of being rollably supported on a slope or incline such as the inclined surfaces 23. For best results, it has been found that the angle of these surfaces 23 and the corresponding angle of the axes of plungers 28 with the horizontal should be approximately 15, although considerable variation may be permitted while still obtaining satisfactory results.

By vertically spacing the sealing rollers [5 from the sealing rollers I9, the seal around the strip S at rollers 19 is maintained when the welded joint J between .theend of that strip and the adjoining end of the next strip S is passing through the other set of sealing rollers l5. As indicated in Fig. l the seal is being made between thestrip S and the .rollers .13 as the joint .J passes through the rollers 15. Conversely, as the joint J passes through the rollers 1.9 the seal is maintained between thestrip 5' and the rollers 15, so that at all times one pair of sealing rollers is tightly .engaging .the strip surface to provide an effective seal.

As shown in Fig. 1, a pair of baflie ribs or plates 31.may be provided above each pair of sealing rolls J5 and IS, with a narrow opening between the baflles for passage of the strip. These bafiles function to catch any foreign material carried along with the strip into the discharge portion of the .muffie, and prevent any substantial amount of .it frombeing carried into the sealing rollers.

effective seal at the discharge 'end of a gas pickling furnace muflle, so as to prevent the pickling gas from escaping into the washing or fluxing tank T, and also to prevent vapors rising from the tank from entering the :muffie.

I claim:

1.. Sealingeconstruction for a chamber containing a fluid medium for treating .a continuous metal strip, including spaced pairs of sealing rollers in said chamber for engaging opposite.

sides of said strip, means yieldingly urging each of said rollers toward and maintaining the same in sealing engagement with the strip, and a support for each pair of rollers having supporting surfaces rollabl-y engaging the strip engaging surfaces of the rollers and oppositely inclined toward the strip.

2. Sealing construction for a chamber containing :a fluid medium for treating a continuous metal strip, including a pair of sealing rollers in said chamber for engaging opposite sides of said strip, means yieldingly urging each of said rollers toward and maintaining the same in sealing engagement with the strip, .and a roller support having surfaces rollably engaging the strip engaging surfaces of said rollers on opposite sides of said strip.

3. Sealin construction for a chamber containing a fluid medium for treating a continuous metal strip, including a roller support in said chamber having roller supporting surfaces on opposite sides of the strip inclined oppositely toward the strip, sealing rollers rollably supported on said surfacesqfor engaging opposite sides of the strip, means yieldingly urging each of said rollers into engagement with the strip, and a flange on each end of the roller support slidably abutting the ends of the rollers supported thereby.

4. Sealing construction for a chamber containing a fluid medium for treating a continuous metal strip, including a roller support in said chamber having roller supporting surfaces on opposite sidesof the strip, sealing rollers rollably supported on said surfaces for engaging opposite sides of the strip, means yieldingly urging each of said rollers into engagement with the strip, and a flange on each end of the roller-support slidably abutting the ends of the rollers supported thereby.

5. Sealing construction for a chamber containing a fluid medium for treating a continuous said strip, means yieldingly urging each of said rollers into engagement with said strip, and a roller support having surfaces oppositely inclined toward said strip and rollably engaging said rollers, said roller support having a slot between said surfaces for passage of said strip.

ROBERT F. RENKIN. 

